diff --git a/src/python/monodomain_2D_vary_parameters_spatially.py b/src/python/monodomain_2D_vary_parameters_spatially.py
index 78a9119..b097b63 100644
--- a/src/python/monodomain_2D_vary_parameters_spatially.py
+++ b/src/python/monodomain_2D_vary_parameters_spatially.py
@@ -259,7 +259,7 @@
 
 # Set the stimulus on half the bottom nodes
 stimComponent = cellML.FieldComponentGet(cellModel, iron.CellMLFieldTypes.PARAMETERS, "membrane/IStim")
-for node in range(1,numberOfXElements/2):
+for node in range(1,int(round(numberOfXElements/2))):
     nodeDomain = decomposition.NodeDomainGet(node,1)
     if nodeDomain == computationalNodeNumber:
         cellMLParametersField.ParameterSetUpdateNode(iron.FieldVariableTypes.U, iron.FieldParameterSetTypes.VALUES, 1, 1, node, stimComponent, stimValue)
@@ -333,7 +333,7 @@
 problem.Solve()
 
 # Now turn the stimulus off
-for node in range(1,numberOfXElements/2):
+for node in range(1,int(round(numberOfXElements/2))):
     nodeDomain = decomposition.NodeDomainGet(node,1)
     if nodeDomain == computationalNodeNumber:
         cellMLParametersField.ParameterSetUpdateNode(iron.FieldVariableTypes.U, iron.FieldParameterSetTypes.VALUES, 1, 1, node, stimComponent, 0.0)